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Solved: Slow Transfer Speeds on Synology NAS

So you’ve got a shiny new Synology NAS and you’ve started storing files on it, videos, music and so forth. Unfortunately, the file transfer speeds are so bad you’re considering buying a turtle and glueing a USB drive to its back to speed up file copying.

After hours of searching the net for an answer, in the end, I found the cause of my woes in a couple of little settings tucked away on the Synology – effectively my Synology NAS wasn’t even trying to use newer/faster versions of the SMB protocol.

In Advanced Settings, set the Maximum SMB protocol to SMB3, I also increased the minimum SMB protocol to SMB2. If your NAS is operating on a private home network, you may want to disable transport encryption mode (use at your own risk) and enable opportunistic locking:

For me on my Synology DS215j, this took my file transfers from around 5MBps to around 80MBps!

30 comments on «Solved: Slow Transfer Speeds on Synology NAS»

Is it necessary to reboot after making the changes? I have the DS218j. First I had used Disk Station to do a 2-way sync on my desktop for the Pictures folder. SLOW. Next I synced the Music folder. Relatively faster. Now I am attempting to sync the Music folder on my tablet (SSD) remembering how much quicker the transfer was on the desktop. File transfer rate = 1 file every 8 minutes. It’s been several days and 473 files remain. This is beyond painful. Many other descriptive words. So in short, I’d like to try these changes now w/o having to start all over because of a required reboot. Thank you!

For anyone wondering, you can do this live. Your time machine backup or file transfers will quietly recover from the extremely brief disconnect. Networking at this level recovers all on its own. You’ll quickly see your time machine backup estimated time drop soon afterward.

Thanks! Just wanted to comment for others that might stumble upon this. Don’t have a gigabit router so was looking for other options to speed up my 1.5mb/s speed. This really worked – cut a 90gb move from 16 hours to 3 hours.

I was really hoping that would be the answer to my problem… unfortunately it didn’t do the trick 🙁 However, my settings wasn’t setup as you prescribe. So I hope that a step in the right direction. Thanks for that.

Good morning. Your hint made my month! Slow speed has been a problem for years for the 1812+: the max. was 25 at its best … I was even considering changing it for a newer model. Now speed is up to 110 which is perfect. Again: Thank you very much and all the best for you and your family.

Hi Giordano, I’m glad it helped! The transport encryption mode adds encryption to SMB V3.0 for security but obviously like any encryption, it comes at a cost so may affect your top speed it its enabled (try it and see!).

Hi Clay, I’m afraid if you’ve lost the credentials to your NAS you have a whole other problem my friend! If you can browse to network shares though, your computer must have some saved credentials you may be able to retrieve. Bob

Clay, There is a reset button on the NAS. Use it VERY CAREFULLY. The Synology web site will say something like hold BRIEFLY and it will reset the password. If you hold it too long it will do a complete reset and you will lose your data. So please, READ the web site first.

I recently purchased and installed a Synology DS418play NAS, using WD 4TB RED drives. After finding Mr McKay’s page on the interwebs,I made the same changes to my NAS as listed above.

Yet, it hasn’t solved the speed transfer issues. When moving three (3) ~4GB files from a PC to the NAS, with the NAS mapped as a network drive, the initial transfer speed is great…some 106mb/sec (Ihave the two NICs bonded, on a gigabit switch). Then, within a few minutes, the transfer rate falls off a cliff, dropping down to 5-6MB/sec.

It appears to be an issue during a multiple file transfer, not a single file transfer.

When you say the issue seems to be when you’re transferring multiple files, are they concurrent or queued? I’m wondering if concurrent copies of large files will have the hard drive head dancing back and forth and it could be the slow down you’re seeing is the caches maxing out. What is your RAID configuration and do you see the same problems copying the same 3 files back to your PC *from* the NAS?

Honestly, I want to throttle the people who suggested I buy a NAS and the replacement supposedly ‘better and faster one’. What a waste of money. I’ve spent the last 5 days trying to upload, transfer and get everything running and syncing smoothly!

Recently installed a DS218, and the upload speed is awful. I made the changes above and I’m still getting upload speed in the single digit KBs range. At this rate, it will take a century or more to transfer my terabytes of photos. Do you have any other suggestions?

Hi Bob, thanks for your response. The DS218 has a wired connection to my Netgear R7000 router. All of my computers are running Win 10. One desktop is also has a wired connection, but the computer where I store the majority of my data is connected via wi-fi (2.4GHz). So far, I’ve tried changing the settings specified above and rebooting. Upon rebooting, the upload speed jumped up to 175Kb/s…very briefly, alas. It then returned to <10Kb/s…

Hi Brandon, I doubt very much that the problem lies with the cable between the Netgear and the Synology but given both have Gigabit ports its probably worth putting a CAT6 cable in there anyway (negligible cost too). The speeds your seeing are so slow however that something else is amiss here and I’m guessing the issue is around the wifi. Have you done a test transfer from the PC that is connected to the Netgear via a cable? This should prove (or disprove) that the connection from the Netgear to the Synology is sound. What signal strength is your computer seeing? If you do a browser based broadband speed test on that computer, what speeds do you see? (I ask because that should theoretically show you the slowest speed on the whole chain which given the speeds above appears to be within your home network).

Hi Bob, I was playing with it again last night and this may be a case of user error. I discovered the upload queue and got better visibility on what what happening. I did what you suggested about moving a single file (2GB) from the wired computer to the NAS, and it transferred in about 2 minutes. I tried the same file from wifi and got a similar result. I’m now moving the folders in smaller pieces (40-50GB at a time). Upload speeds bounce around between 1-5 MB/s…is this normal?

There’s still a lot of factors to consider I’m afraid but the critical one is that MBps is not the same as Mbps (its all in the case), a MegaBYTE is eight times larger than a Megabit. If you are using, for example, the Wireless-G (since you said your wifi 2.4Ghz) then the theoretical link speed is 54Mbps (Megabits) now in reality this equates to a 25Mbps transfer rate. To measure this in MegaBYTES you need to divide it by 8 so we’re talking around 3MBps.

The truth is, if you want to do heavy lifting in terms of file transfer you either need a cable or a dual band wifi. Personally I swear by Ubiquiti Wireless Access Points, the pro versions of which give me a real-world transfer speed of around 25 MegaBYTES per second.

Hi Bob, Thanks for the advice and information. Continued testing over the weekend, looks like it’s working well. I switched the wifi to 5Ghz (802.11ac according to the router manual) and uploads are generally 5-10 MBps (not Mbps) according to the upload queue. The key is to not try moving terabytes in one chunk, I think. I moved a couple folders >150GB and upload times were in the 12-24 hr range. Anyway, thanks again!

Hey Brandon, I’m glad things seem to have sped up. One thing I hadn’t considered is that when copying multiple files from my PC I never do ‘concurrent’ copies, that is where you set a file copying, then separately set another copying, then another, etc. – this is because Windows isn’t smart enough to just push each additional file to a queue, it copies a chunk of each in a cycle, which means there’s a bigger admin overhead (and if you have an old HD, the read head will be jumping about a lot more). If you need to copy multiple files, I’d only do it where you are able to select them all at the same time and do a copy/paste (sometimes I’ll even move files on my PC to the same folder before moving them to my NAS to facilitate this). All the best Bob